Polishing pad with removal features

ABSTRACT

The invention provides a polishing pad comprising a polishing element and an adhesive layer provided on the bottom surface of the polishing element for attaching the polishing element to a polishing device. To protect the adhesive layer and prevent unintentional adhering of the polishing element, the polishing pad is also provided with a protective liner adhered to and protectively covering the adhesive layer. To facilitate removal of the protective liner, the protective liner includes an extended pull tab and the polishing element includes an extended removal tab.

FIELD OF THE INVENTION

This invention pertains generally to a polishing pad, and moreparticularly to a polishing pad for use in chemical-mechanicalpolishing.

BACKGROUND OF THE INVENTION

Polishing processes are used in the manufacture of microelectronicdevices to form flat surfaces on semiconductor wafers, field emissiondisplays, and many other microelectronic substrates. For example, themanufacture of semiconductor integrated circuit (IC) devices generallyinvolves the formation of various process layers, selective removal orpatterning of portions of those layers, and deposition of yet additionalprocess layers on a semiconductor wafer. The IC process layers caninclude, by way of example, insulation layers, gate oxide layers,conductive layers, and layers of metal or glass, etc. It is generallydesirable in certain steps of the IC wafer process that the uppermostsurface of the process layers be planar, i.e., flat. Relatively flattersurfaces allow the use of more sensitive, higher density patterning onsubsequent layers.

Chemical-mechanical polishing or planarization (“CMP”) is a process usedto planarize IC wafer process layers wherein a deposited material, suchas a conductive or insulating material, is polished to planarize thewafer for subsequent process steps. The process has been labeled“chemical-mechanical” because the surface of the wafer is subjected tomechanical abrasion combined with other more purely chemical action suchas oxidation. The worked surface of the IC wafer is subjected to arotating or otherwise moving pad in the presence of slurry. The slurrycontains both abrasive particles and chemical activators, modulators oraccelerants.

Most commercial applications of CMP rely on specialized machine toolsthat include a rotating pad platen, a wafer carrier and a slurryapplicator. The rotating platen is upward facing, circular and adaptedto receive a disk shaped pad. Like the pad platen, the wafer carrier isalso equipped with a rotation mechanism. The wafer carrier is positionedover the pad. As both the wafer carrier and the pad rotate, the wafercarrier directs the worked surface of the wafer onto pad. The polishingcomposition (also referred to as a polishing slurry) generally isintroduced onto the rotating polishing pad.

The disk shaped polishing pads typically have one side designated forcontacting the wafer while the opposite side contacts the platen. Anadhesive layer is included on the platen side of the pad to fix the padto the plate. A protective liner can be adhered to the adhesive layer toprotect the adhesive layer from contamination and to prevent unwantedsticking to other surfaces before installation. This protective liner ispeeled off the pad before installion on the platen. This pealing steppresents a difficulty, however, because clean room operators using CMPtools must wear protective gloves. Gloves make the first step ofgripping the liner for removal difficult. Operators are known to addressthe gripping problem by using a knife or razor blade, which can resultin damage to the pad.

Accordingly, there is a need for an adhesive-backed polishing pad thatis better adapted for easy removal of the protective liner. There isalso a need for a polishing pad that can be easily removed from theplaten. The invention provides such a polishing pad and a method ofmanipulating a polishing pad that addresses these needs.

BRIEF SUMMARY OF THE INVENTION

The invention provides a polishing pad having a polishing element thatdefines an outer perimeter that may, for example, be circular in shape.To secure the polishing element to a platen, an adhesive layer isprovided on a bottom surface of the polishing element. A protectiveliner is adhered to the adhesive layer so as to protectively cover theadhesive layer. The protective liner and adhesive layer interacttogether so that the protective liner can be removed and discarded whilethe adhesive layer remains on the bottom surface. To facilitate peelingof the protective liner from the polishing pad, a pull tab is connectedto the protective liner and extends beyond the perimeter defined by thepolishing element. Extending the pull tab beyond the perimeter improvesthe ability of an operator to securely grasp the protective liner.

To facilitate removal of the polishing element from the platen after aperiod of use, a removal tab is connected to the polishing element whichalso extends beyond the perimeter. The adhesive layer that is providedon the bottom surface of the polishing element is substantially absentfrom the removal tab. Accordingly, the removal tab can be grasped andpulled in a direction generally away from the platen to peel thepolishing element from the platen. Moreover, the removal tab furtherfacilitates peeling of the protective liner from the polishing pad byenabling an operator to simultaneously grasp the removal tab and pulltab and to pull the removal tab and pull tab in generally oppositedirections.

Thus, an advantage of the invention is that it provides a polishingelement with a protective liner having a pull tab attached whichenhances an operator's ability to remove the protective liner. Anotheradvantage is that the invention facilitates the removal of the polishingelement from a polishing device. These and other advantages and featuresof the invention will be apparent from the drawings and detaileddescription provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top perspective view of a polishing pad including apolishing element with a removal tab and a protective liner with a pulltab.

FIG. 2 is a side elevational view of the polishing pad of FIG. 1illustrating the polishing element and protective liner being peeledapart.

FIG. 3 is a top perspective view of a polishing pad wherein the removaltab and the pull tab generally overlap.

FIG. 4 is a perspective view of a polishing pad element with a removaltab being peeled from the platen of a polishing device.

FIG. 5 is a top perspective view of an alternative view of a polishingpad wherein the removal tab and the pull tab include respectiveprojection portions.

FIG. 6 is a side elevational view of the polishing pad of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

Now referring to the drawings, wherein like reference numbers refer tolike elements, there is illustrated in FIGS. 1 and 2 a polishing pad 100designed in accordance with the teachings of the invention. Thepolishing pad 100 includes a polishing element 102 that generallydefines a perimeter 104. In the preferred and illustrated embodiment,the perimeter 104 is circular in shape with a width designed by arrow106. As will be appreciated, in the preferred embodiment of a circularpolishing element 102, the width designated by arrow 106 corresponds toa diameter. However, in other embodiments, the perimeter 104 can haveany other suitable shape such as, for example, square or octagonal.Furthermore, the width of the polishing element 102 as indicated byarrow 106 can be any suitable value, preferably between about 10millimeters to about 200 millimeters.

The polishing element 102 also includes a top surface 110 and a parallelbottom surface 112, which provides the polishing element with a uniformthickness and a generally planar shape. The top surface 110 is adaptedfor motion adjacent to and polishing of a substrate, such as asemiconductor wafer, while the bottom surface 112 is adapted forattachment to a polishing device. Additionally, in an embodiment, thepolishing element 102 may include a plurality of pores disposed into thetop surface 110, the bottom surface 112, or both. Likewise, in anembodiment, the polishing element may include a plurality of groovesdisposed into the top surface 110, the bottom surface 112, or both.

Referring to FIG. 1, the polishing pad 100 also includes a removal tab120 connected to the polishing element 102 that extends in a radialdirection beyond the perimeter 104 defined by the polishing element 102.Preferably, the removal tab 120 extends about 3 millimeters or morebeyond the circular perimeter 104 and, more preferably, about 6millimeters or more beyond the perimeter. In the illustrated embodiment,the removal tab 120 can have a generally parabolic shape. However, inother embodiments, the removal tab can have a crescent shape, arectangular shape, or any other appropriate shape. The removal tab 120has a thickness defined by spaced-apart top and bottom surfaces 122, 124that, in the illustrated embodiment, are co-planar with the respectivetop and bottom surfaces 110, 112 of the polishing element 102.

The removal tab 120 can be formed integrally with the polishing element102, or the removal tab can be formed separately from and later attachedto the polishing element. The removal tab 120 and polishing element 102can be made from any suitable material, and typically but notnecessarily can be made from the same material. Typically, polishingelements of polishing pads are made from a polymer resin. Preferably,the polymer resin is selected from the group consisting of thermoplasticelastomers, thermoplastic polyurethanes, thermoplastic polyolefins,polycarbonates, polyvinylalcohols, nylons, elastomeric rubbers,elastomeric polyethylenes, polytetrafluoroethylenes,polyethyleneterephthalates, polyimides, polyaramides, polyarylenes,polyacrylates, polystyrenes, polymethylmethacrylates, copolymersthereof, and mixtures thereof. More preferably, the polymer resin is athermoplastic polyurethane resin.

Referring to FIG. 2, to attach the polishing element 102 to a polishingdevice, there is disposed on the bottom surface 112 of the polishingelement an adhesive provided in the form of an adhesive layer 128. Theadhesive can be any suitable adhesive such as, for example, a pressuresensitive adhesive. Preferably, the adhesive layer 128 is disposedacross the bottom surface 114 within the confines of the perimeter 104such that it is substantially absent from the removal tab 120.

Referring to FIGS. 1 and 2, to protect the adhesive layer 128 andprevent the polishing pad 100 from unintentionally adhering to objects,the polishing pad 100 also includes a protective liner 130. Theprotective liner 130 has a first surface 132 and a parallel secondsurface 134 that desirably provide the protective liner with a uniformthickness. The first surface 132 can be adhered to the bottom surface112 of the polishing element 102 by way of the adhesive layer 128 toprotectively cover the adhesive layer. To facilitate removing theprotective liner 130 from the bottom surface 112 when attaching thepolishing element 102 to a polishing device, the protective liner ispreferably made from a flexible thermoplastic or a thermoset polymerthat demonstrates a substantial non-stick or peel-away characteristic.In an alternative embodiment, the protective liner is made fromwax-coated paper. Accordingly, when the protective liner 130 is removedfrom the polishing element 102, the adhesive layer 128 will remainbonded to the bottom surface 112 of the polishing element 102.

Like the polishing element 102, the protective liner 130 defines asecond perimeter 136. In the illustrated and preferred embodiment, thesecond perimeter 136 has the same circular shape as well as the samewidth as designated by arrow 106 as the first perimeter 104.Accordingly, the protective liner 130 and polishing element 102 arecoterminous with each other. As such, the width of the protective linerindicated by arrow 106 can be any suitable value, preferably betweenabout 10 millimeters to about 200 millimeters. In other embodiments, theshapes and widths could vary substantially between the protective linerand polishing element.

Connected to the protective liner 130 and extending beyond the secondperimeter 136 in a radial direction is a pull tab 140. Preferably, thepull tab 140 extends about 3 millimeters or more beyond the circularsecond perimeter 136 and, more preferably, about 6 millimeters or morebeyond the second perimeter. In the illustrated embodiment, the pull tab140 has a generally parabolic shape similar to that of the removal tab120. However, in other embodiments, the pull tab can have a crescentshape, a rectangular shape, or any other appropriate shape.

The pull tab 140 can be formed integrally with the protective liner 130or it can be formed separately from and later attached to the protectiveliner. Additionally, the pull tab 140 can have a first surface 142 and asecond surface 144 that, in the illustrated embodiment, are co-planar tothe respective first and second surfaces 132, 134 of the protectiveliner 130. Preferably the pull tab 140 is made from the same flexible,non-stick thermoplastic material as the protective liner 130.Furthermore, the adhesive layer 128 adhering the protective liner 130 tothe polishing element 102 is also substantially absent from the pull tab140.

An advantage of providing a polishing pad having the foregoing structureis the simplified and enhanced removal of the protective liner from thepolishing element. Referring to FIG. 1, because both the removal tab 120and the pull tab 140 extend beyond the first and second perimeters 104,136 defined by the polishing element 102 and the respective protectiveliner 130, the tabs are suitably exposed for grasping even by therubber-gloved hands of an operator. As illustrated in FIG. 2, theremoval tab 120 and the pull tab 140 can then be manually pulled inopposite directions as indicated by arrows 148. As will be appreciated,this results in peeling the protective liner 130 from the polishingelement 102. Because of the non-stick or peel-away characteristic of theprotective liner material, the adhesive layer 128 will remain on thebottom surface 112 of the polishing element 102.

Another advantage is realized in the embodiments wherein the adhesivelayer is absent from the removal tab 120 and the pull tab 140. Byproviding the adhesive-free tabs for the operator to grasp, theoperator's hands will not become adhered to or otherwise ensnarled withthe polishing element 102 and protective liner 130. A related advantageis that the adhesive-free removal tab 120 provides the operator with atab connected to the polishing element 102 that can be securely grasped.Specifically, the operator's hands can grasp around the top and bottomsurfaces 122, 124 of the removal tab 120, thereby facilitatingmanipulation of the polishing element 102 during its application to thepolishing device.

In the illustrated embodiment of the polishing pad 100, removal of theprotective liner 120 is further enhanced by locating the removal tab 120and the pull tab 140 at different locations. For example, referring toFIG. 1, the polishing element 102 includes a centroid 150. In theillustrated embodiment, the centroid 150 corresponds to the center ofthe circular perimeter 104. The removal tab 120 and the pull tab 130 arelocated at an angular offset from each other with respect to thecentroid 150. Angularly offsetting the removal tab 120 and pull tab 140increasingly exposes those tabs for enhanced grasping. Preferably, theangular offset is about 20° to about 40°, and more preferably is about30°, which adequately exposes the tabs 120, 140 but continues tofacilitate peeling of the protective liner 130 from the polishingelement 102 by simply pulling the tabs in generally opposite directions,as would not be possible if the tabs were offset at an angle of about180°.

Of course, the removal tab and the pull tab need not be located at anangular offset. Referring to FIG. 3, for example, an embodiment of thepolishing pad 200 is illustrated having a polishing element 202 with aremoval tab 220 and a protective liner 230 having a pull tab 240. Theremoval tab 220 and pull tab 240 have an angular offset of approximately0° with respect to a centroid 250 of the polishing element 202 such thatthe removal tab and pull tab are substantially overlaying each other. Anadvantage of overlaying the removal tab 220 and pull tab 240 is thesimplification and possible space reduction in packaging anddistribution of the polishing pad.

Another advantage of providing a polishing pad having a polishingelement with a removal tab is realized in the facilitated removal of thepolishing element from a polishing device. For instance, referring toFIG. 4, there is illustrated some of the components of a polishingdevice 160. The polishing device 160 can include a polishing table orplaten 162 on which the polishing pad 100 designed in accordance withthe preferred embodiment of the invention is supported. Of course, otherembodiments of the polishing device may work with the variousembodiments of the inventive polishing pad. Also included, as part ofthe polishing device is a carrier 164 supported above the platen 162 andpolishing pad 100. A substrate can be mounted and retained on thecarrier 164.

To carryout the polishing operation, the carrier 164 can be rotatedand/or orbited with respect to the platen 162, the platen rotated and/ororbited with respect to the carrier, or both can be rotated and/ororbited simultaneously. Additionally, for providing a polishing slurryor composition from a reservoir, the polishing device 160 can include anozzle 166 communicating with the reservoir that delivers the polishingcomposition to the area of interaction between the polishing pad 100 andthe substrate.

As will be appreciated, to secure the polishing pad 100 to the platen162, the bottom surface 112 is adhered onto the platen via the adhesivelayer 128. Due to the adhesive attachment, the polishing element 102resists removal from the platen 162 during, for instance, replacement ofa worn polishing element. However, as illustrated, the polishing element102 and the perimeter 104 it defines are substantially of the samedimension as the platen 162. Accordingly, the removal tab 120 extendsbeyond the platen 162 and is exposed for grasping by an operator. Thisenables grasping and pulling the removal tab 120 in a directiongenerally away from the platen 162, as indicted by arrow 170, to peelthe bottom surface from the platen. Hence, the removal tab 120 providesboth a tab to grasp the polishing element 102 with and leverage forpulling the polishing element from the platen 162.

The removal tab need not extend beyond the platen to facilitate removalof the polishing element. For instance, it will be appreciated that inembodiments wherein the platen is substantially larger than thepolishing element, the removal tab will lay adjacent the top surface ofthe platen. However, if the removal tab is substantially adhesive free,it can be readily grasped, lifted, and pulled from the platen in theabove described manner to remove the polishing element.

Illustrated in FIGS. 5 and 6 is another embodiment of a polishing pad300 adapted to further enhance and assist the removal of a protectiveliner from a polishing pad element. The polishing pad 300 includes apolishing element 302 having a top surface 310 and a parallel bottomsurface 312 that desirably provides the polishing element with a uniformthickness. The polishing element 302 also defines a perimeter 304. Theperimeter 304 may have any suitable shape including, for example,circular. Connected to the polishing element 302 and extending beyondthe perimeter is a removal tab 320.

To attach the polishing element 302 to a polishing device, the polishingpad 300 also includes an adhesive layer 328 deposited onto the bottomsurface 312 of the polishing element. Preferably, the removal tab 320 issubstantially absent of adhesive.

To protect and isolate the adhesive layer 328, the polishing pad 300also includes a protective liner 330 having a first surface 332 and aparallel second surface 334 that provides desirably the protective linerwith a uniform thickness. The first surface 332 of the protective liner330 is adhered to the bottom surface 312 of the polishing element 302via the adhesive layer 328. The protective liner 330 also defines asecond perimeter 336 that can be co-extensive with the first perimeter304. To simplify removal of the protective liner 302, the polishing pad300 is provided with a pull tab 340 connected to the protective linerand extending beyond the perimeter 336. Preferably, the pull tab 340 isalso substantially absent of adhesive.

To further enhance grasping of the exposed removal tab 320 and pull tab340, one or both tabs can be made substantially thicker than thecomponents they are connected to. For example, the pull tab 340 includesa liner projection portion 342 that projects from a plane defined by thefirst surface 332 of the protective liner 330. The liner projectionportion 342 may extend coextensively to a plane defined by the topsurface 310 of the polishing element 302. An advantage of the linerprojection portion 342 is that it substantially thickens the pull tab340, thereby providing the operator with more to grasp when removing theprotective liner 330. The liner projection portion 342 may be formedintegrally with the protective liner 330 or separately from theprotective liner and later attached thereto.

Similarly, the removal tab 320 can include a pad projection portion 322that projects from a plane defined by the bottom surface 312 of thepolishing element 302. The pad projection portion 322 may projectcoextensively to a plane defined by the second surface 334 of theprotective liner 330. The pad projection portion 322 also substantiallythickens the removal tab 320 to provide an operator with more to graspwhen manipulating the polishing element. Like the liner projectionportion 342, the pad projection portion 322 can be formed integrallywith the polishing element 302 or formed separately and later attachedthereto.

Accordingly, the invention provides a polishing pad having a polishingelement, an adhesive layer for adhering the polishing element to apolishing device, and a protective liner adhered to the polishingelement via the adhesive layer. To facilitate peeling the protectiveliner from the polishing element, the protective liner includes a pulltab and the polishing element includes a removal tab. Pulling the pulltab and removal tab in opposite directions peels the protective linerfrom the polishing element. Additionally, the removal tab facilitatessubsequently peeling the polishing pad from a polishing device.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

1. A polishing pad comprising: (a) a polishing element having aperimeter; (b) a removal tab connected to the polishing element andextending beyond the perimeter; (c) a protective liner having a firstsurface adhered to the polishing element; and (d) a pull tab connectedto the protective liner and extending beyond the perimeter of thepolishing element.
 2. The polishing pad of claim 1, wherein thepolishing element has a centroid located within the perimeter, and theremoval tab and the pull tab are angularly offset from each other withrespect to the centroid.
 3. The polishing pad of claim 2, wherein theangle of offset is about 20 degrees to about 40 degrees.
 4. Thepolishing pad of claim 2, wherein the removal tab and the pull tabextend about 3 millimeters or more beyond the perimeter.
 5. Thepolishing pad of claim 2, wherein the removal tab is integral with thepolishing element.
 6. The polishing pad of claim 5, wherein the pull tabis integral with the protective liner.
 7. The polishing pad of claim 6,wherein the protective liner has a second and perimeter, the secondperimeter is coterminous with the perimeter of the polishing element. 8.The polishing pad of claim 7, wherein the perimeter of the polishingelement and the second perimeter are circular.
 9. The polishing pad ofclaim 8, wherein each of the polishing element and the second perimeteris about 10 millimeters to about 200 millimeters in width.
 10. Thepolishing pad of claim 2, wherein the pad element and the removal tabcomprise a polymer.
 11. The polishing pad of claim 10, wherein thepolymer is selected from the group consisting of thermoplasticelastomers, thermoplastic polyurethanes, thermoplastic polyethylenes,polytetrafluoroethylenes, polyethyleneterephthalates, polyimides,polyaramides, polyarylenes, polyacrylates, polystyrenes,polymethylmethacrylates, and thermoset polymers.
 12. The polishing padof claim 5, wherein the protective liner and the pull tab comprise apolymer.
 13. The polishing pad of claim 1, further comprising anadhesive layer between the protective liner and the polishing element,the adhesive layer adhering the protective liner to the pad element. 14.The polishing pad of claim 13, wherein the adhesive layer comprises apressure sensitive adhesive.
 15. The polishing pad of claim 1, whereinthe polishing element has a centroid located within the perimeter, andthe locations of the removal tab and the pull tab angularly correspondto each other with respect to the centroid.
 16. A method of manipulatinga polishing pad comprising: (i) providing a polishing pad including apolishing element having a bottom surface and a perimeter, a removal tabconnected to the polishing element and extending beyond the perimeter, aprotective liner adhered to the polishing element, and a pull tabconnected to the protective liner and extending beyond the perimeter;(ii) separately grasping the removal tab and the pull tab; (iii) pullingthe removal tab and the pull tab in generally opposite directions topeel the protective liner from the polishing element; (iv) applying thebottom surface to a platen of a polishing device to adhere the polishingpad to the polishing device.
 17. The method of claim 16, furthercomprising: (v) releasing the removal tab.
 18. The method of claim 17,wherein the polishing element has a centroid located within theperimeter, and the removal tab and the pull tab are angularly offsetfrom each other with respect to the centroid.
 19. The method of claim18, further comprising: (vi) re-grasping the removal tab; and (vii)pulling the removal tab in a direction generally away from the platen topeel the bottom surface from the platen, thereby removing the polishingpad from the polishing device.
 20. A polishing pad comprising: (a) apolishing element having a perimeter, a top surface, and a bottomsurface; (b) a removal tab connected to the polishing element andextending beyond the perimeter, the removal tab including a padprojection portion projecting from the bottom surface; (c) a protectiveliner having a first surface adhered to the polishing element; and (d) apull tab connected to the protective liner and extending beyond theperimeter of the polishing element, the pull tab including a linerprojection portion projecting from the first surface.